<mm id = A style = line-height:1ex>
<script>
	n = 50;
	sin = Math.sin;

	setInterval(function()
	{
		b = '';
		
		for(i = 0; i < n; i++)
			for(b += '<br>', j = 0; j < n; j++) 
			{// to do ...
				
				b += 0;

			}
		
		A.innerHTML = b;
		++t;
	}, 18);
</script>
